Constantine

Constantine was the Roman Emperor who called for the first international council of Christians which is known as the Council of Nicaea in 325 AD.  It was held at Nicaea, which is now known as Iznik, Turkey.

Constantine was follower of the Sol Invictus sun-god cult who, it is said, on his deathbed accepted baptism in Christianity on the outside chance that the Christians had the right idea.  He figured that professing a belief in Christianity could not hurt him.  He must have figured that a little water on the head would not cause much harm.  He seemed to consider it as a cheap form of after-life insurance.

Constantine, while considered to have legitimized Christianity, seems to have been a follower of the Sol Invictus Sun-God cult.

He is said to have spent the latter part of his life as a high priest of the Sol Invictus cult, at least until he claimed to have converted to Christianity.

He seems to have considered Christianity as a possible means of consolidating the fragmenting Roman Empire.  He realized that many in his empire would not wish to embrace Christianity so he encouraged the Christianization of Pagan Religions. This resulted in many Pagan ideas being given new Christian identities even though they were nothing more than a new name used for the Pagan beliefs.  Isis was changed by the Christians into Mary, the 'Mother of God' so that the new Religion of Christianity would be somewhat more palatable to Isis worshipers.